A couple of easy ones?

[S Schroeder]

Hi all-
I have a couple of quick questions. When I purchased my car most of the front end was rebuilt(ie tie rods, struts, ball joints). That being the case, I don't know what those components feel like as they wear out. I have started to help a buddy work on his newly aquired '71 that has a shimmy in the front end. What are the different characteristics of:
1. bad ball joints
2. bad tie rods
3. Bad alignment

When we went to replace the struts we found nearly brand new KYB GR2's that are in perfect shape. The wheels are factory steel with new tires and we have had the balance checked twice - it is fine.

Question #2: His head lights pulse a bit and the voltmeter (factory '73 center console guage)reads erratic. The car has a new alternator (3 weeks old), starts on the first crank and the idiot light is not glowing at all. Any ideas? Thanks in advance-
S Schroeder

[Bobbitt]

Not sure about the ball joints, but try this to check the tie rods:

While standing outside the car, gently hold the steering wheel with your right hand using your thumb and pointer finger. Gently place your left fingertips on the front left wheel. Now gently move the wheel back and forth. Not much, just a few degrees. The front wheels should not turn when doing this. If you can feel any free free play in the wheel, you probably need new tie rods. The free play would be noticed by the steering wheel moving freely for a couple of degrees without feeling anything on the wheel. It is kind of difficult to describe, but it is noticable with a gentle touch. Since your car is probably ok, compare the two. After some practice, you will be able to check it without needing to touch the tire.

I said that the tie rods are probably bad because a few other things could cause this free play. First is the plastic tolerance ring under the top bearing in the steering column. Those have a habit of breaking up. If it is bad, you can feel some free play at the steering wheel. Try moving the steering up and down. You should not feel any free play if the parts are good. Other possible problems could be the bearings in the universal joints backing out slightly or a steering rack problem. Those are not very likely though. I used to design steering systems for a living and commonly saw that sort of problem, but I have never hear it on a Porsche.

You can check for a bad alignment through tire wear. The tread pattern should be worn uniformly across the tire profile. Over inflation of the tires wears the middle first, any other wear problem would be alignment related. But, if you need to replace tie rods or ball joints, you need to align the suspension anyway.

Are the wheel bearings OK? Loose/worn wheel bearings could cause a shimmy. If the shimmy is only under braking, it could be warped front rotors. When does the car shimmy?

Bobbitt

[S Schroeder]

Thanks Bobbitt-
The shimmy feels very similar to the tires being out of balance. It happens sparatically at different speeds and is much less noticeable when two adults are in the car. It is also in some ways similar to the pogo effect when you have a blown shock and the car is riding on the torsion bars. It is not just a steering wheel shake, but more of a cowl shake. Wierd to say the least.
Thanks, Scott S.

[rich]

This may not be of much use but, I had a vibration that I could have sworn was coming from the front end. After checking the front over several times we discovered that we had a rear tire with a broken cord. Another time I had a u-joint on a suzuki samari feel like a rear wheel bearing. If the problem persists you may want to look a little closer at the rear shocks, axles and tires. Good Luck

[BeeJay]

I had the same problem once. It took me two weeks to figure it our. But my sway bar had somehow gotten shoved to one side. Once I re centered it, the shimy went away.

[BeeJay]

I had the same problem once. It took me two weeks to figure it out. But my sway bar had somehow gotten shoved to one side. Once I re centered it, the shimy went away.

[Conrad W Peden]

If you can feel the 'shimmy' in the steering wheel its most likely the front shocks. If the you feel the 'shimmy' your seat its the rear.